The purpose of this project is to continue studies which are allowing us to obtain a better understanding of the effects of hypertension on WAIS and neuropsychological test measures with advancing age. Continuation of our ongoing longitudinal studies will allow us to: 1) follow subjects, already tested three times, for an additional five years (Time 4 testing); 2) perform Time 3 testing for subjects tested initially during the 1981-1984 grant period; 3) perform Time 2 testing for subjects tested initially during the 1985-1990 grant period; 4) expand the number of subjects in our overall cross-sectional design. The objective is to characterize age-related changes over time in cognitive functioning as affected by hypertension. We are particularly interested in change over time and levels of performance as predicted by: (1) unmedicated baseline systolic and diastolic blood pressure levels (across the full range and within the normal or untreated range) (2) as a function of diagnostic category; severe; less severe; normotensive. Change over time is analyzed by comparing different mathematical (statistical) models for "individual change." The question here is whether different dynamic models for characterizing change hold equally well for hypertensive and normotensive individuals and for fluid, speed, memory, and crystallized components of intellect. Recent factor analytic studies of the WAIS indicate that this four-component model reflects the relationship among subtests more accurately than does the traditional Verbal-Performance test model. Subtest composition of the four components is as follows: 1) Fluid (Block Design, Picture Completion, Picture Arrangement, Object Assembly); 2) Psychomotor Speed (Digit Symbol); 3) Memory or Short-Term Retrieval (Arithmetic, Digit Span); and 4) Crystallized (Information, Comprehension, Similarities, Vocabulary). Analyses employing the Verbal-Performance model will also be conducted for purposes of comparability with existing literature. The study is guided by a hypothetical "pathophysiology construct" in which vascular and metabolic effects are seen as producing accelerated change in cognitive functioning over time. Our data (and the data of others) suggest that hypertension unmedicated blood pressures at baseline are the best markers of severity.